The present invention relates to a non-contact continuous type sensing device for a flowmeter and a sensing method thereof and, more particularly, to a non-contact continuous type sensing device for a flowmeter and a sensing method thereof that are not affected by external magnetic members while sensing the flowing condition of a fluid.
A flowmeter is a tool mounted in a fluid pipe for detecting the fluid flow. Conventional flowmeters generally include a metering device therein. The metering device has a rotating member that can be driven to rotate by a fluid, such that the metering device can calculate the total flow of the fluid flowing therethrough. The metering device of early flowmeters includes a contact-type (mechanical) mechanism including members that are driven to rotate by each other. After long-term use, error or malfunction of the driving effect between the members occurs due to mechanical factors and impurities in the fluid, leading to adverse influence to the sensitivity and accuracy of metering. Non-contact type flowmeters using magnetic induction are developed accordingly. However, the conventional non-contact type flowmeters still have the following disadvantages in practical use. Firstly, magnetic members of the conventional non-contact type flowmeters are apt to be attracted or interfered by strong external magnetism, leading to an inaccurate metering result. Secondly, the conventional flowmeters can only meter the volumetric flow and cannot sense the flowing direction of the fluid. In fact, in the current conditions of severe lack and imbalance of water resources, the possibility and necessity of mutual support or transaction between administration units owing water resources often exist. In this case, a flowmeter mounted in piping to sense the flowing direction of the fluid can provide certain convenience in the support or transaction.
In view of the foregoing disadvantages, Applicant of the present invention filed an invention patent application entitled “NON-CONTACT CONTINUOUS TYPE SENSING DEVICE FOR A FLOWMETER AND SENSING METHOD THEREOF” (Taiwan Invention Patent No. 1418767) which discloses a flowmeter including a movable member connected to an operating member. When the movable member is driven by a fluid, the movable member actuates the operating member to displace. A projector is mounted above the operating member for projecting signals onto the operating member. At least two regions are defined in a side of the operating member facing the projector. At least one of the regions can reflect the signal projected thereon to cause a change in the signal density in the space between the projector and the operating member when the operating member is passing through the space. Thus, the projecting power of the projector is affected to sense the movement condition of the operating member to thereby know the flowing condition of the fluid.
However, projection of signals by the projector onto the operating member is often proceeded intermittently, such that the detected flow condition often presents interrupted detection results in which the abscissa axis is the time. Thus, improvement to the precision of the detection results is desired.